Imbed is just a variation in spelling of embed, which means to put something inside something else, usually deep so it will not come loose.
Its derivatives include embedded, embedding, and embedment. The spelling variation continues through all forms: imbedded, imbedding, and imbedment. (The last imbedment is almost obsolete.)
The e spelling is so preferred that it is advisable to use simply to avoid having your readers think you misspelled.